A helper class to handle basic SQLite operations in Flutter.

database_helper.dart

import 'dart:async';

import 'package:path/path.dart';
import 'package:sqflite/sqflite.dart';

/// A very simple class that we recognize as SQLite-compatible
abstract class DatabaseModel {
  Map<String, Object?> toMap();
}

/// A very simple helper class to manage local SQLite databases.
/// It should be adjusted as needed.
class DatabaseHelper<T> {
  static const String databaseFileName = 'deebee.db';
  static const int databaseVersion = 1;
  static const String tableName = 'entries';
  static const String tableSchema = 'id INTEGER PRIMARY KEY, age INTEGER';

  Future<Database> initializeDB() async {
    String path = await getDatabasesPath();
    return openDatabase(
      join(path, databaseFileName),
      onCreate: (database, version) async {
        await database.execute(
          "CREATE TABLE $tableName($tableSchema)",
        );
      },
      version: databaseVersion,
    );
  }

  /// Insert a model into the database
  Future<int> insert(DatabaseModel model) async {
    int result = 0;
    final Database db = await initializeDB();
    result = await db.insert(
      tableName,
      model.toMap(),
    );
    return result;
  }

  /// Retrieve all models from the database.
  /// Specify a function to construct an Object from the returned JSON.
  Future<List<DatabaseModel>> retrieve(DatabaseModel Function(Map<String, Object?>) mapFunc) async {
    final Database db = await initializeDB();
    final List<Map<String, Object?>> queryResult = await db.query(tableName);
    return queryResult.map((e) => mapFunc(e)).toList();
  }

  /// Delete an entry where a variable matches a value
  Future<void> delete(String variable, Object value) async {
    final db = await initializeDB();
    await db.delete(
      tableName,
      where: "$variable = ?",
      whereArgs: [value],
    );
  }
}